Photosensitive transfer material

ABSTRACT

A photosensitive transfer material comprises a temporary substrate having provided thereon an alkali-soluble thermoplastic resin layer, an intermediate layer, and a photosensitive resin layer in this order, the interlaminar adhesion in the transfer material being the smallest at the interface between the thermoplastic resin layer and the temporary substrate. The photosensitive resin layer can be transferred to a permanent substrate without involving failure due to fine dust, air bubbles or unevenness of the permanent substrate. An image can be formed with the transfer material by adhering the transfer material to a permanent substrate at least under heat and, after stripping the temporary substrate, imagewise exposing the photosensitive resin layer to light, and processing the transferred layers to develop the photosensitive resin layer. If the thermoplastic resin layer and the intermediate layer are first removed with a processing method with which the photosensitive resin layer is not substantially developed and then the photosensitive resin layer is developed using a processing solution other than used for revmoving the thermoplastic resin layer and the intermediate layer, excessive fatigue of the developing solution for the photosensitive resin layer and unevenness of development can be prevented.

This is a Continuation of application No. 07/996,126 filed Dec. 23,1992, now abandoned.

FIELD OF THE INVENTION

This invention relates to a photosensitive transfer material suitablefor dry transfer onto a substrate with an uneven surface and to an imageformation method using the same. The photosensitive transfer materialand image formation method according to the present invention are suitedfor the production of color filters to be used in liquid crystaldisplays, etc. or for the production of printed circuit boards, etc.

BACKGROUND OF THE INVENTION

Image forming materials for transferring a photosensitive resin layeronto a substrate are known from, for example, JP-B-56-40824 (U.S. Pat.No. 3,884,693; the term "JP-B" as used herein means an "examinedpublished Japanese patent application"). These types of image formingmaterials are used in the manufacture of printed circuit boards,intaglio or relief printing plates, name plates, multicolor printingproofs, offset printing plates, screen printing stencils, etc. Thetransfer material is composed of a temporary substrate, a separatinglayer, and a photopolymerizable layer, and image formation using thetransfer material is carried out by adhering the photopolymerizablelayer to a permanent substrate, stripping the temporary substrate offthe transfer material, exposing the photopolymerizable layer to lightvia the separating layer, and developing the exposed photopolymerizablelayer to form an image on the permanent substrate. The separating layerserves as an oxygen barrier so that the transfer material can be handledand exposed in an air atmosphere. Having a very small thickness of fromabout 0.5 to 5 μm, the separating layer does not adversely affect theresolving power.

However, where the substrate to which a photo polymerizable layer is tobe transferred has an uneven surface, it often happens that air bubblesare formed between the substrate and the very thin photopolymerizablelayer, resulting in a failure of transfer.

JP-A-2-213849 (European Patent 373,438; the term "JP-A" as used hereinmeans an "unexamined published Japanese patent application") discloses atransfer material having an intermediate layer of a polyvinyl alcoholderivative, etc. between a temporary substrate and a photosensitiveresin layer. Provision of the intermediate layer is directed toimproving releasability of the temporary substrate and dissolvingcharacteristics of the intermediate layer, with no consideration beinggiven to transfer properties in the case where the transfer material istransferred to a permanent substrate having an uneven surface.

JP-A-63-309946 (U.S. Pat. Nos. 4,902,363 and 4,939,029) points out theoccurrence of transfer failure due to insufficient adhesion of atransfer layer to a permanent substrate where the substrate has fineirregularities on its surface or where the substrate and/or the transferlayer have thereon fine particles such as refuse and dust. In order toprevent such adhesion failure, the publication teaches the use of acompressive temporary substrate. This means is certainly effective butis still insufficient for preventing of forming bubbles where anon-tacky photosensitive resin layer is transferred at room temperatureto a substrate with a surface roughness equal to the thickness of thephotosensitive resin layer.

Japanese Patent Application No. 120228/91 (corresponding to U.S. patentapplication Ser. No. 07/827,765 wherein Japanese Patent Application No.9292/91 is also included) discloses a transfer method using aphotosensitive transfer material comprising a temporary substrate,particularly a gelatin-coated plastic film, having thereon athermoplastic resin layer, a separating layer, and a photosensitiveresin layer in this order, in which the photosensitive resin layer isadhered to a permanent substrate, and the temporary substrate and thethermoplastic resin layer are simultaneously stripped off to transferthe photosensitive resin layer onto the permanent substrate. Accordingto this method, however, release between the thermoplastic resin layerand the separating layer is not always easily controlled, which is adisadvantage in automating the release operation.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a photosensitivetransfer material which can achieve transfer of the photosensitive resinlayer thereof to a permanent substrate without involving transferfailure due to fine dust, air bubbles, unevenness of the permanentsubstrate surface, and to provide an image formation method using thesame.

Another object of the present invention is to provide a photosensitivetransfer material which enables exposure to light in air, and to providean image formation method using the same.

A further object of the present invention is to provide a photosensitivetransfer material which can achieve transfer of the photosensitive resinlayer thereof to a permanent substrate with satisfactory release fromits temporary substrate, and to provide an image formation method usingthe same.

A still further object of the present invention is to provide aphotosensitive transfer material which forms an image on a permanentsubstrate without contaminating the substrate, and to provide an imageformation method using the same.

A still further object of the present invention is to provide aphotosensitive transfer material which prevents an electrical shock orattraction of dust due to electrification on stripping the temporarysubstrate, and to provide an image formation method using the same.

A still further object of the present invention is to provide an imageformation method which prevents fatigue of a developing solution orunevenness of development.

The first to fourth objects of the present invention can be accomplishedby a photosensitive transfer material comprising a temporary substratehaving provided thereon an alkali-soluble thermoplastic resin layer, anintermediate layer, and a photosensitive resin layer in this order, theinterlaminar adhesion in the transfer material being the smallest at theinterface between the thermoplastic resin layer and the temporarysubstrate. The first to fourth objects of the present invention can alsobe accomplished by an image formation method using such a photosensitivetransfer material which comprises adhering the photosensitive resinlayer to a permanent substrate at least under heat and, if desired,under pressure, stripping the temporary substrate off the alkali-solublethermoplastic resin layer, imagewise exposing the photosensitive resinlayer to light preferably through the alkali-soluble thermoplastic resinlayer and the intermediate layer, and developing the photosensitiveresin layer to form an image on the permanent substrate.

The fifth object of the present invention can be accomplished by aphotosensitive transfer material having the above-mentioned structureand further characterized in that the temporary substrate has a surfaceresistivity of not more than 10¹³ Ω.

The sixth object of the present invention can be accomplished by animage formation method comprising removing the alkali-solublethermoplastic resin layer and the intermediate layer by using aprocessing solution capable of dissolving the alkali-solublethermoplastic resin layer and the intermediate layer but substantiallyincapable of developing the photosensitive resin layer and thendeveloping the photosensitive resin layer.

The photosensitive transfer material according to the present inventioncomprises a temporary substrate, an intermediate layer, and aphotosensitive resin layer, with a thermoplastic resin layer having acushioning effect and satisfactory release properties from the temporarysubstrate being interposed between the temporary substrate and theintermediate layer. The photosensitive resin layer can be adhered to apermanent substrate with an uneven surface without entrapping airbubbles owing to the cusioning effect of the thermoplastic resin layer,and the photosensitive resin layer and the intermediate layer can easilybe transferred to the permanent substrate by stripping off the temporarysubstrate with satisfactory release. A monochromatic or multicolor imagecan thus be formed on the permanent substrate through an easy transferoperation with the photosensitive transfer material of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The temporary substrate which can be used in the present inventionpreferably is made of a material which is satisfactorily releasable(i.e., sufficient to carry out development the photosensitive resinlayer) from a thermoplastic resin layer, which is chemically andthermally stable, and which is flexible. Suitable temporary substratesinclude a thin sheet of polyethylene terephthalate, polycarbonate,polyethylene, polypropylene, etc. and laminates thereof.

In order to obtain satisfactory releasability, the temporary substrateto be used should not be subjected to a surface treatment, such as aglow discharge treatment nor should it be provided with a under coatinglayer of gelatin, etc.

The thickness of the temporary substrate suitably from about 5 to about300 μm, and preferably is from about 20 to about 150 μm.

In some cases, depending on the transfer conditions, a thermoplasticresin may ooze out to the sides during the transfer process andcontaminate the permanent substrate. Since in the present invention athermoplastic resin which is soluble in an aqueous alkaline solution isused such contamination can be avoided. Having alkali solubility, thethermoplastic resin contaminating the substrate can be removed with easein a subsequent processing step.

The aqueous alkaline solution for removal of the thermoplastic resin mayor may not be the same as the alkaline developing solution to be usedfor development of a photosensitive resin. The expression "aqueousalkaline solution" as used herein means a dilute aqueous solution of analkaline substance which may contain a small amount of an organicsolvent miscible with water in order to accelarate permiation of thesolution into the resin. Suitable alkaline substances include alkalimetal hydroxides (e.g., sodium hydroxide and potassium hydroxide),alkali metal carbonates (e.g., sodium carbonate and potassiumcarbonate), alkali metal bicarbonates (e.g., sodium bicarbonate andpotassium bicarbonate), alkali metal silicates (e.g., sodium silicateand potassium silicate), alkali metal metasilicates (e.g., sodiummetasilicate and potassium metasilicate), triethanolamine,diethanolamine, monoethanolamine, morpholine, tetraalkylammoniumhydroxides (e.g., tetramethylammonium hydroxide), and sodium tertiaryphosphate. The aqueous alkaline solution preferably contains thealkaline substance in a concentration of from about 0.01 to about 30% byweight based on the total weight of the solution (the same hereinafter)and has a pH ranging from about 8 to about 14.

The water-miscible organic solvents which may be present in the aqueousalkaline solution include methanol, ethanol, 2-propanol, 1-propanol,butanol, diacetone alcohol, ethylene glycol monomethyl ether, ethyleneglycol monoethyl ether, ethylene glycol mono-n-butyl ether, benzylalcohol, acetone, methyl ethyl ketone, cyclohexanone, ε-caprolactone,γ-butyrolactone, dimethylformamide, dimethylacetamide,hexamethylphosphoramide, ethyl lactate, methyl lactate, ε-caprolactam,and N-methylpyrrolidone. The concentration of the water-miscible organicsolvent is from about 0.1 to about 30% by weight. The aqueous alkalinesolution may further contain a conventional surface active agent in aconcentration preferably of from about 0.01 to about 10% by weight.

The thermoplastic resin composition constituting the thermoplastic resinlayer preferably has a softening point of not higer than about 80° C.and of higher than room temperature. Specific examples of alkali-solublethermoplastic resins having a softening point of not more than about 80°C. are a saponification product of an ethylene-acrylic ester copolymer,a saponification product of a styrene-(meth)acrylic ester copolymer, asaponification product of a vinyltoluene(meth)acrylic ester copolymer,poly(meth)acrylates, a saponification product of a (meth)acrylic estercopolymer such as a (meth)acrylic ester and vinyl acetate copolymer(e.g., a butyl (meth)acrylate-vinyl acetate copolymer), and mixturesthereof. In addition, alkali-soluble organic high polymers selected fromthose having a softening point of about 80° C. or lower described inPlastic Seino Binran, edited by Nippon Plastic Kogyo Renmei (JapanPlastics Industry Association) and Zen-Nippon Plastic Seikei KogyoRengokai (All Japan Federation of Plastics Molding Industry), publishedby Kogyo Chosakai (Industrial Investigation Commission) (Oct. 25, 1968)can be employed. Further, organic high polymers whose softening point isabove about 80° C. may also be used in combination with variousplasticizers compatible therewith so as to drop the substantialsoftening point to about 80° C. or less. For the purpose of controllingadhesion to a temporary substrate, these organic high polymers maycontain various other polymers, supercooling substances, adhesionimproving agents, surface active agents, parting agents, and so on aslong as the substantial softening point does not exceed 80° C.

Examples of suitable plasticizers are polypropylene glycol, polyethyleneglycol, dioctyl phthalate, diheptyl phthalate, dibutyl phthalate,tricresyl phosphate, cresyl diphenyl phosphate, and biphenyl diphenylphosphate.

The thermoplastic resin layer preferably has a thickness of at least 6μm more preferably at least 10 μm, and most preferably at least 12 μm.If the thickness of this layer is 5 μm or less, the layer may fail tocompletely absorb the unevenness of 1 μm or more of a permanentsubstrate. The preferred upper limit of the thickness of thethermoplastic resin layer is about 100 μm, more preferably about 50 μm,and particularly about 25 μm from the standpoint of developability andproduction suitability.

The intermediate layer is provided to prevent permeation of oxygen intothe photosensitive material, especially which is comprised aphotopolymerizable composition. Such a layer preventsphotopolymerization radical from comsumption by oxygen. The intermediatelayer can also acts to prevent contamination of the photosensitive resinby the thermoplastic resin composition.

The material for the intermediate layer is not particularly limited andthe intermediate layer may be prepared from conventional materials aslong as it is dispersible or soluble in water or an aqueous alkalinesolution and exhibits low oxygen permeability. Sutable materials for theintermediate layer include those described in JP-A-46-2121 (CanadianPatent 992,789) and JP-B-56-40824 (U.S. Pat. No. 3,884,693), etc., forexample, polyvinyl ether/maleic anhydride polymers, water-soluble saltsof a carboxyalkyl cellulose, water-soluble cellulose ethers,water-soluble salts of carboxyalkylated starch, polyvinyl alcohol,polyvinyl pyrrolidone, various polyacrylamides, various water-solublepolyamides, water-soluble salts of polyacrylic acid, gelatin, ethyleneoxide polymers, water-soluble salts of various types of starch andanalogues thereof, styrene-maleic acid copolymers, maleate resins, andcombinations of two or more thereof.

Of these materials, a combination of polyvinyl alcohol and polyvinylpyrrolidone is preferred. The polyvinyl alcohol to be used preferablyhas a degree of saponification of at least 80%. The proportion ofpolyvinyl pyrrolidone in the combination preferably is from about 1 toabout 75% by weight, more preferably from about 1 to about 60% byweight, and most preferably from about 10 to about 50% by weight, basedon the total solids content of the intermediate layer. If it is lessthan 1% by weight, sufficient adhesion to the photosensitive resin layermay not be obtained. If it exceeds 75% by weight, the oxygen barrierproperties of the intermediate layer would be reduced.

The intermediate layer is very thin, preferably having a thickness offrom about 0.1 to about 5 μm, and more preferably from about 0.5 toabout 2 μm. If the thickness is less than about 0.1 μm, the oxygenpermeability is too high. If the thickness exceeds about 5 μm,development or removal of the intermediate layer would tend to take toomuch time, and absorption of the uneveness of the surface of theparmanent substrate would tend to be difficult.

It is preferable that the photosensitive resin layer soften and becometacky at a temperature of 150° C. or lower and higher than roomtemperature (e.g., 25° C.) and that it be thermoplastic. Mostphotosensitive resin layers obtained from known photopolymerizablecompositions have the above-mentioned characteristics. Some of the knownphotopolymerizable compositins may be further modified by addition of athermoplastic resin binder or a compatible plasticizer.

Any of the known photosensitive resins described, e.g., in JP-A-3-282404(U.S. Pat. No. 5,155,005) may be used as materials for thephotosensitive resin layer of the present invention. Suitablephotosensitive resins include photosensitive compositions comprising anegative type diazo resin and a binder, photopolymerizable compositions,photosensitive resin compositions comprising an azide compound and abinder, and cinnamic acid-type photosensitive resin compositions, withphotopolymerizable compositions being particularly preferred. Thephotopolymerizable compositions basically comprise a photopolymerizationinitiator, at least one photopolymerizable monomer, and a binder.

While known photosensitive resins include those developable with anaqueous alkaline solution and those developable with an organic solvent,the former are preferred from the standpoint of prevention ofenvironmental pollution and safety of the working environment.

The thickness of the photosensitive resin layer is generally from about0.1 μm to about 100 μm. When the photosensitive layer is adhered onto ametal-surface of a substrate, such as a copper-clad substrate, thethickness of the layer is preferably from about 0.1 μm to about 100 μm,more preferably from 0.5 to 80 μm, and particularly preferably fromabout 0.8 to about 50 μm, and when the photosensitive layer is used forforming a color filter the thickness of the photosensitive layer is fromabout 0.1 to about 10 μm, more preferably from about 0.5 μm to about 7μm, and partaicularly preferably from about 0.8 to about 5 μm.

The aqueous alkaline solution which can be used as an alkalinedeveloping solution in the present inventin is a dilute aqueous solutionof an alkaline substance which may contain a small amount of an organicsolvent miscible with water. Suitable alkaline substances include alkalimetal hydroxides (e.g., sodium hydroxide and potassium hydroxide),alkali metal carbonates (e.g., sodium carbonate and potassiumcarbonate), alkali metal bicarbonates (e.g., sodium bicarbonate andpotassium bicarbonate), alkali metal silicates (e.g., sodium silicateand potassium silicate), alkali metal metasilicates (e.g., sodiummetasilicate and potassium metasilicate), triethanolamine,diethanolamine, monoethanolamine, morpholine, tetraalkylammoniumhydroxides (e.g., tetramethylammonium hydroxide), and sodium tertiaryphosphate. The aqueous alkaline solution preferably contains thealkaline substance in a concentration of from about 0.01 to about 30% byweight and has a pH ranging from about 8 to about 14.

The water-miscible organic solvents which may be present in the aqueousalkaline solution include methanol, ethanol, 2-propanol, 1-propanol,butanol, diacetone alcohol, ethylene glycol monomethyl ether, ethyleneglycol monoethyl ether, ethylene glycol mono-n-butyl ether, benzylalcohol, acetone, methyl ethyl ketone, cyclohexanone, ε-caprolactone,γ-butyrolactone, dimethylformamide, dimethylacetamide,hexamethylphosphoramide, ethyl lactate, methyl lactate, ε-caprolactam,and N-methylpyrrolidone. The concentration of the water-miscible organicsolvent is from about 0.1 to about 30% by weight. The aqueous alkalinesolution may further contain a conventional surface active agent in aconcentration preferably of from about 0.01 to about 10% by weight.

The developing solution may be used either as a bath or as a spray.Development, i.e., removal of the unhardened portion of thephotosensitive resin layer with the developing solution, can be effectedwhile rubbing the exposed photosensitive resin layer with a rotatingbrush or wet sponge, etc. The developing solution is preferably used ata temperature of from about 20° to about 60° C., more preferably fromabout 25° to about 50° C. If necessary, the development step may befollowed by a step of washing with water.

After transfer and exposure, removal of the thermoplastic resin layerand the intermediate layer, and development of the photosensitive resinlayer to remove the unhardened portion, may be carried outsimultaneously. However, in order to reduce unevenness of development orfatigue of the developing solution, the processing of these three layersis preferably carried out in two divided stages in which thethermoplastic resin layer and the intermediate layer are first removedby a processing method by which the photosensitive resin layer is notsubstantially developed and the photosensitive resin layer is thendeveloped.

As a processing for removal of the thermoplastic resin layer and theintermediate layer the above-described aqueous alkaline solution or theaqueous alkaline solution containing a water-insoluble organic solventin a small amount may be used. In order to substantially preventdevelopment of the photosensitive resin layer, it is preferred to use anaqueous solution of an alkali compound having a weaker basicity.

The same processing solution as for the photosensitive resin may be usedas a processing solution to remove the thermoplastic resin layer and theintermediate layer under milder conditions, such as liquid temperature,spray pressure, rubbing force, etc., than those used for developing thephotosensitive resin layer so as to minimize the influences on thephotosensitive resin layer. However, where a photosensitive materialhaving two alkali-soluble layers as in the present invention isprocessed in two stages under different development conditions, it isdifficult to stably control the respective processing conditions inactual operations. Moreover, since the processing proceeds slowly, theremoval of the thermoplastic resin layer and the intermediate layerrequires much time, resulting in poor working efficiency. Hence, twostage processing for minimizing the influence of removal of thethermoplastic resin layer and the intermediate layer on thephotosensitive resin layer can be achieved by choosing a processingsolution for removing the thermoplastic resin layer and the intermediatelayer whose dissolving rate for the thermoplastic resin layer and theintermediate layer is different from that for the photosensitive resinlayer. For example, when the processing solution to be used for removingthe thermoplastic resin layer and the intermediate layer is such thatthe minimum time required for development of the photosensitive resinlayer is at least twice the minimum time required for removal of thethermoplastic resin layer and the intermediate layer, only thethermoplastic resin layer and the intermediate layer are removed withoutsubstantial development of the photosensitive resin layer. After thethermoplastic resin layer and the intermediate layer are removed, thephotosensitive resin layer can be developed with a developing solutiontherefor. In this case, the developing solution for the photosensitiveresin layer is prevented from being fatigued by removal of thethermoplastic resin layer and the intermediate layer. Further, sincedevelopment of the photosensitive resin layer can be conducted with nothermoplastic resin layer or intermediate layer thereon, thephotosensitive resin layer is not subject to unevenness of removal whichmay arise from unevenness of development of the thermoplastic resinlayer and, as a result, a uniformly developed image can be obtained.

More specifically, in order to efficiently conduct the removal of thethermoplastic resin layer and the intermediate layer, it is preferablethat the thermoplastic resin layer and the intermediate layer be removedwith an aqueous solution of an alkaline substance of weaker basicitythan the developing solution for the photosensitive resin layer. Weakerbasic alkaline substances which can be used in the developing solutionfor the thermoplastic resin layer and the intermediate layer includeethanolamines, e.g., monoethanolamine, diethanolamine, andtriethanolamine, with triethanolamine of weak basicity beingparticularly preferred.

The concentration of the alkaline substance in the aqueous solutionsuitably ranges from about 0.01 to about 10% by weight. If it is lessthan about 0.01% by weight, too much time will be required for removalof the thermoplastic resin layer and intermediate layer and the workingefficiency will be reduced. If it exceeds 10% by weight, it is possiblethat the photosensitive resin layer may also be developed. Aparticularly preferred concentration is from about 0.1 to about 5% byweight.

The liquid temperature of the processing solution used to remove thethermoplastic resin layer and the intermediate layer is preferably lowso as to avoid adverse influences on the photosensitive resin layer, buta too low liquid temperature extends the removal time and reduces theworking efficiency. If the liquid temperature exceeds 40° C., it ispossible that the photosensitive resin layer may also be developed.Accordingly, a preferred liquid temperature is from 20° to 40° C.

The removal of the thermoplastic resin layer and the intermediate layermay be conducted by using a bath or a spray of the processing solution.The removal may be effected by rubbing with a rotating brush or wetsponge, or by combining these method.

If desired, the photosensitive resin layer may contain dyes or pigments.All the pigments preferably uniformly dispersed in the photosensitiveresin layer preferably to a particle size of not greater than aoubt 5μm, and particularly not greater than about 1 μm. In the production ofcolor filters, pigments having a particle size of not greater than about0.5 μm are preferred.

Specific examples of suitable dyes or pigments are Victoria Pure Blue BO(C.I. 42595), Auramine (C.I. 41000), Fat Black HB (C.I. 26150), MonoliteYellow GT (C.I. Pigment Yellow 12), Permanent Yellow GR (C.I. PigmentYellow 17), Permanent Yellow HR (C.I. Pigment Yellow 83), PermanentCarmine FBB (C.I. Pigment Red 146), Hoster Perm Red ESB (C.I. PigmentViolet 19), Permanent Ruby FBH (C.I. Pigment Red 11), Fastel Pink BSupra (C.I. Pigment Red 81), Monastral Fast Blue (C.I. Pigment Blue 15),Monolite Fast Black B (C.I. Pigment Black 1), and carbon. Suitablepigments useful in the production of color filters include C.I. PigmentRed 97, C.I. Pigment Red 122, C.I. Pigment Red 149, C.I. Pigment Red168, C.I. Pigment Red 177, C.I. Pigment Red 180, C.I. Pigment Red 192,C.I. Pigment Red 215, C.I. Pigment Green 7, C.I. Pigment Green 36, C.I.Pigment Blue 15:1, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6, C.I.Pigment Blue 22, C.I. Pigment Blue 60, and C.I. Pigment Blue 64.

It is preferable to provide a thin protective sheet on thephotosensitive resin layer for protection against contamination ordamage during storage. The protective sheet may be made of the same orsimilar materials as used as a temporary substrate but must have easyrelease from the photosensitive resin layer. Suitable protective sheetsinclude silicone paper, a polyolefin sheet, and apolytetrafluoroethylene sheet. The protective sheet preferably has athickness of from about 5 to 100 μm. An especially preferred protectivesheet is a polyethylene or polypropylene film having a thickness of from10 to 30 μm.

The photosensitive transfer material according to the present inventioncan be prepared by coating a thermoplastic resin layer coating solutionon a temporary substrate followed by drying to form a thermoplasticresin layer, applying an intermediate layer coating solution containinga solvent incapable of dissolving the thermoplastic resin layer on thethermoplastic resin layer followed by drying to form an intermediatelayer, and applying a photosensitive resin layer a coating compositioncontaining a solvent incapable of dissolving the intermediate layer onthe intermediate layer followed by drying to form a photosensitive resinlayer.

The transfer material may also be prepared advantageously by adhering(1) a protective sheet having formed thereon a photosensitive resinlayer and (2) a temporary substrate having formed thereon athermoplastic resin layer and an intermediate layer in this order, withthe photosensitive resin layer and the intermediate layer facing eachother; or by adhering (1) a temporary substrate having formed thereon athermoplastic resin layer and (2) a protective sheet having formedthereon a photosensitive resin layer and an intermediate layer in thisorder, with the thermoplastic resin layer and the intermediate layerfacing each other.

When the photosensitive resin layer of the thus prepared photosensitivematerial is adhered to a permanent substrate and the temporary substrateis stripped off, (usually at room temperature) the film and the humanbody are electrically charged in some cases to give an irritatingelectrical shock to the worker. Further, the electrification causes thefilm to attract dust, which may produce unexposed areas in thesubsequent exposure step, causing pinholes.

In order to prevent the electrification, it is preferable to provide anelectrically conductive layer on at least one side of the temporarysubstrate to reduce the surface resistivity of the substrate to about10¹³ Ω or less, and particularly not more than about 10¹² Ω, or thetemporary substrate itself may be made electrically conductive so as tohave a surface resistivity of not more than about 10¹³ Ω, andparticularly not more than about 10¹² Ω.

The temporary substrate itself can be rendered electrically conductiveby incorporating thereinto a conductive substance, such as fineparticles of a metal oxide or an antistatic agent. Suitable metal oxidesto be incorporated include at least one crystalline metal oxide selectedfrom zinc oxide, titanium oxide, tin oxide, aluminum oxide, indiumoxide, silicon oxide, magnesium oxide, barium oxide, and molybdenumoxide and/or a composite oxide thereof. Suitable antistatic agents to beincorporated include anionic surface active agents, such asalkylphosphate compounds (e.g., "ELECTROSTRIPPER A" produced by Kao SoapCo., Ltd., and "ELENON No. 19" produced by Dai-ichi Kogyo Seiyaku Co.,Ltd.); amphoteric surface active agents, such as betaine compounds(e.g., "AMOGEN K" produced by Dai- ichi Kogyo Seiyaku Co., Ltd.); andnonionic surface active agents, such as polyoxyethylene fatty acidesters (e.g., "NISSAN NONION L" produced by Nippon Oils & Fats Co.,Ltd.) and polyoxyethylene alkyl ethers (e.g., "EMULGEN 106, 120, 147,420, 220, 905, and 910" produced by Kao Soap Co., Ltd. and "NISSANNONION E" produced by Nippon Oils & Fats Co., Ltd.). In addition, othernonionic surface active agents such as polyoxyethylene alkyl phenolethers, polyhydric alcohol fatty acid esters, polyoxyethylene sorbitanfatty acid esters, and polyoxyethylene alkylamine compounds, may also beemployed.

The electrically conductive layer which can be formed on the temporarysubstrate is properly selected from known conductive layers. Among them,a conductive layer containing fine particles of at least one crystallinemetal oxide selected from ZnO, TiO₂, SnO₂, Aι₂ O₃, In₂ O₃, SiO₂, MgO,BaO, and MoO₃ and/or a composite oxide thereof is preferred because itsconductivity is unaffected by humidity. The fine particles of thecrystalline metal oxide or composite metal oxide preferably have avolume resistivity of not higher than about 10⁷ Ω·cm, and particularlynot higher than about 10⁵ Ω·cm, and a prefered particle size of fromabout 0.01 to about 0.7 μm, and particularly preferably from about 0.02to about 0.5 μm.

The details for preparation of the conductive fine particles of thecrystalline metal oxide or composite metal oxide are described inJP-A-56-143430 (U.S. Pat. No. 4,495,276). In brief, the conductive fineparticles may be obtained by a process comprising preparing fine metaloxide particles by calcining and then subjecting the particles to a heattreatment in the presence of a different atom for improvingconductivity, a process comprising preparing fine metal oxide particlesby calcining in the presence of a different atom for improvingconductivity, or a process comprising preparing fine metal oxideparticles by calcining in an atmosphere having a diminished oxygenconcentration to introduce oxygen defects. The different atom to be usedis, for example, Aι or In for ZnO; Nb or Ta for TiO₂, or Sb, Nb, or ahalogen atom for SnO₂. The different atom is preferably added in anamount of from about 0.01 to about 30 mol %, and particularly from about0.1 to about 10 mol %.

These conductive fine particles are usually used in an amount of fromabout 0.05 to about 20 g/m², and preferably of from about 0.1 to about10 g/m² of the photosensitive transfer material.

The conductive layer may contain, as a binder, gelatin, a celluloseester (e.g., cellulose nitrate, cellulose triacetate, cellulosediacetate, cellulose acetate butyrate, and cellulose acetatepropionate), a homo- or copolymer formed from vinylidene chloride, vinylchloride, styrene, acrylonitrile, vinyl acetate, a C₁₋₄ alkyl acrylate,vinylpyrrolidone, etc., a soluble polyester, a polycarbonate, a solublepolyamide, and so on. In dispersing the conductive fine particles in thebinder, a dispersant, such as a titanium type dispersant or a silanetype dispersant, may be added. A binder crosslinking agent may also beused.

The titanium type dispersants to be used include the titanate couplingagents described in U.S. Pat. Nos. 4,069,192 and 4,080,353, and"PLENACT" (trade name) produced by Ajinomoto Co., Inc. Examples of thesilane type dispersants to be used include vinyltrichlorosilane,vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane,γ-glycidoxypropyltri-methoxysilane, andγ-methacryloxypropyltrimethoxysilane. These silane type dispersants arecommercially available as silane coupling agents from, e.g., Shin-EtsuChemical Industry Co., Ltd.

The binder crosslinking agents to be used include epoxy typecrosslinking agents, isocyanate type crosslinking agents, and aziridinetype crosslinking agents.

A preferred conductive layer is formed by coating a dispersion of theconductive fine particles in a binder on a temporary substrate or byforming a prime coat on a temporary substrate and then adheringconductive fine particles thereto.

Where the conductive layer is provided on the temporary substrate on theside opposite to the photosensitive resin layer, it is preferable tofurther provide a hydrophobic polymer layer on the conductive layer toassure scratch resistance. The hydrophobic polymer layer can be formedby coating a solution of the polymer in an organic solvent or an aqueouslatex of the polymer to a dry weight of from about 0.05 g/m² to about 1g/m² of the photosensitive transfer material.

Examples of suitable hydrophobic polymers include cellulose esters(e.g., nitrocellulose and cellulose acetate), vinyl polymers formed fromvinyl chloride, vinylidene chloride, vinyl acrylate, etc., organicsolvent-soluble polyamide resins, and polyester resins. The hydrophobicpolymer layer may contain slip agents for imparting slip properties,such as organic carboxylic acid amides described in JP-A-55-79435 (U.S.Pat. No. 4,275,146), or matting agents. Such a hydrophobic polymerlayer, if provided, exerts substantially no influence upon the effect ofthe conductive layer. The under coat, if provided, may includevinylidene chloride copolymers as described in JP-A-51-135526 (U.S. Pat.No. 4,087,574) and U.S. Pat. Nos. 3,143,421, 3,586,508, 2,698,235, and3,567,452; diolefin copolymers formed from butadiene, etc. as describedin JP-A-51-114120 (U.S. Pat. No. 4,429,039) and U.S. Pat. No. 3,615,556;copolymers formed from glycidyl acrylate or glycidyl methacrylate asdescribed in JP-A-51-58469; polyamide-epichlorohydrin resins asdescribed in JP-A-48-24923 (U.S. Pat. No. 3,877,673); and copolymersformed from maleic anhydride as described in JP-A-50-39536 (U.S. Pat.No. 4,124,395 ).

In addition to the above-described conductive layers, those described inJP-A-56-82504, JP-A-56-143443 (U.S. Pat. No. 4,416,963), JP-A-57-104931,JP-A-57-118242 (U.S. Pat. No. 4,394,441), JP-A-58-62647, andJP-A-60-258541 are also useful.

In a particularly preferred embodiment of the conductive layerformation, a conductive layer is formed by co-extruding a plasticmaterial, which may be the same or different from that of the temporarysubstrate, containing conductive fine particles together with a film ofthe temporary substrate. In this case, a conductive layer with excellentadhesion and scratch resistance can easily be obtained, and there is noneed to provide the above-mentioned hydrophobic polymer layer or a undercoat.

Where a conductive layer is formed by coating, coating may be carriedout by any known technique, such as roller coating, air knife coating,gravure coating, bar coating, curtain coating, and the like.

For the purpose of improving slip properties or preventing blockingbetween the photosensitive resin surface layer and the back of thetemporary substrate, it is useful to coat the back of the temporarysubstrate with a slip composition containing known fine particles or arelease composition containing a silicone compound.

Image formation by the use of the photosensitive transfer materialaccording to the present invention can be carried out as follows.

The photosensitive resin layer from which a protective sheet, if any, isremoved is adhered onto a permanent substrate under heat orheat-pressure. Adhering may be conducted by means of a known laminatoror a known vacuum laminator. An autocut laminator may be used forincreasing productivity. Then, the temporary substrate is stripped off,and the photosensitive resin layer transferred to the permanentsubstrate is exposed to light through a prescribed mask, and generally,also through the thermoplastic resin layer and the intermediate layer,followed by development processing (including removal of thethermoplastic resin layer and the intermediate layer, and which isconducted in one step or in two separated steps as describedhereinabove). Development processing can be effected in a known manner,i.e., by soaking in a solvent or an aqueous processing solution,especially an aqueous alkaline solution or by spraying a solvent or anaqueous processing solution, especially an aqueous alkaline solution,while, if desired, rubbing with a brush, etc. or applying ultrasonicwaves.

A multicolor image can be formed by repeating the above-mentionedprocedure using a plurality of photosensitive transfer materialsdiffering in the color of the photosensitive resin layer.

After forming an image on a parmanent substrate, a photosensitive resinlayer having a different color from that of the image is transferredthereon and then exposure and development is conducted. By repeating theformation of images having different colors on the substrate amulticolor image can be obtained.

The photosensitive transfer material of the present invention isadvantageously useful mainly in the production of printed circuitboards, the production of color filters for multicolor images,especially liquid crystal displays, and the production of a protectivelayer of the color filters.

In the production of printed circuit boards, a known copper-cladlaminated sheet may be used as a substrate. In the production of colorfilters, a known glass plate or a soda glass plate having formed thereona silicon oxide film may be used as a substrate.

The present invention will now be illustrated in greater detail withreference to Examples, but it should be understood that the presentinvention is not deemed to be limited thereto. All the parts are givenby weight unless otherwise indicated.

EXAMPLE 1

A coating composition having formulation H1 shown below was coated on a100 μm thick polyethylene terephthalate (PET) film as a temporarysubstrate and dried to form a 20 μm thick thermoplastic resin layer.

    ______________________________________                                        Formulation H1:                                                               ______________________________________                                        Methyl methacrylate/2-ethylhexyl                                                                        15    parts                                         acrylate/benzyl methacrylate/methacrylic                                      acid copolymer (copolymerization                                              molar ratio = 55/28.8/11.7/4.5; weight                                        average molecular weight (Mw) = 90000)                                        Polypropylene glycol diacrylate                                                                         6.5   parts                                         (Mw = 822)                                                                    Tetraethylene glycol dimethacrylate                                                                     1.5   parts                                         p-Toluenesulfonamide (plastitizer)                                                                      0.5   part                                          Benzophenone (plastitizer)                                                                              1.0   part                                          Methyl ethyl ketone       30    parts                                         ______________________________________                                    

A coating composition having formulation B1 shown below was coated onthe thermoplastic resin layer and dried to form a 1.6 μm thickintermediate layer.

    ______________________________________                                        Intermediate Layer Formulation B1:                                            ______________________________________                                        Polyvinyl alcohol ("PVA 205" produced                                                                  130 parts                                            by Kuraray Co., Ltd.; degree of                                               saponification = 80%)                                                         Polyvinyl pyrrolidone ("PVP K-90"                                                                      60 parts                                             produced by GAF Corp.)                                                        Fluorine containing surfactant ("Surfulon                                                              10 parts                                             S-131" produced by Asahi Glass                                                Co., Ltd.)                                                                    Distilled water          3350 parts                                           ______________________________________                                    

Photosensitive coating compositions having the formulation shown inTable 1 below were coated on each of four intermediate layers and driedto form photosensitive resin layers colored in black (B1 layer) red (Rlayer), green (G layer) ,blue (B layer) respectively having a thicknessof 2 μm.

A protective sheet of polypropylene having a thickness of 12 μm was thenbonded by processing on each of the photosensitive resin layers toobtain red, blue, green and black photosensitive transfer materials,respectively.

                  TABLE 1                                                         ______________________________________                                                         R       B       G     K                                                       Layer   Layer   Layer Layer                                  Formulation      (g)     (g)     (g)   (g)                                    ______________________________________                                        Benzyl methacrylate/                                                                           60      60      60    60                                     methacrylic acid co-                                                          polymer (73/27 by mol;                                                        viscosity = 0.12)                                                             Pentaerythritol tetra-                                                                         43.2    43.2    43.2  43.2                                   acrylate (photopolymerizable                                                  monomer)                                                                      Michler's ketone 2.4     2.4     2.4   2.4                                    (photopolymerization                                                          initiator)                                                                    2-(o-Chlorophenyl)-4,5-                                                                        2.5     2.5     2.5   2.5                                    diphenylimidazole dimer                                                       (photopolymerization                                                          initiator)                                                                    Irgazin Red BPT (red)                                                                          5.4     --      --    --                                     Sudan Blue (blue)                                                                              --      5.2     --    --                                     Copper phthalocyanine                                                                          --      --      5.6   --                                     (green)                                                                       Carbon black (black)                                                                           --      --      --    5.6                                    Methyl cellosolve                                                                              560     560     560   560                                    acetate                                                                       Methyl ethyl ketone                                                                            280     280     280   280                                    ______________________________________                                    

A color filter was formed by using the resulting color photosensitivetransfer materials as follows.

The red photosensitive transfer material from which the protective sheethad been removed was adhered to a 1.1 mm thick transparent glasssubstrate under heat (130° C.) and pressure (0.8 kg/cm²) by means of alaminator ("VP-II" manufactured by Taisei Laminator K.K.), and thetemporary substrate was stripped off the thermoplastic resin layer.

The photosensitive resin layer was exposed to light through a prescribedmask and then developed with a 1% sodium carbonate aqueous solution toremove the unnecessary part thereby to form a pattern of red pixels.

The green photosensitive transfer material was adhered to the glasssubstrate having thereon the red pattern, stripped off the temporarysubstrate, exposed to light, and developed in the same manner as aboveto form a pattern of green pixels.

The same procedure was repeated by using the blue photosensitivetransfer material and the black photosensitive transfer material to forma color filter on the transparent glass substrate.

In all the above procedures, the temporary substrate had satisfactoryrelease properties from the respective thermoplastic resin layer. Theresulting color filter exhibited satisfactory adhesion to the glasssubstrate with no lack of pixels and was also free from contamination.

EXAMPLE 2

Color (red, green, blue, and black) photosensitive transfer materialswere prepared in the same manner as in Example 1. The red photosensitivetransfer material was adhered to a 1.1 mm thick glass substrate in thesame manner as in Example 1, and the temporary substrate was stripped atthe interface between the thermoplastic resin layer and the substrateand removed.

The red photosensitive resin layer was exposed to light through aprescribed photomask and soaked in a 1% triethanolamine aqueoussolution. While being soaked, the thermoplastic resin layer and theintermediate layer were removed by lightly rubbing with a sponge. Then,the unnecessary part of the photosensitive resin layer was removed bydeveloping in a 1% sodium carbonate aqueous solution to form a patternof red pixels on the glass substrate.

The same procedure was repeated by successively using the green, blue,and black photosensitive transfer materials to form a color filter onthe transparent glass substrate.

The resulting color filter suffered from no lack of pixels or colorunevenness, exhibited good adhesion to the substrate, and was free fromcontamination.

COMPARATIVE EXAMPLE 1

Color (red, green, blue, and black) photosensitive transfer materialswere prepared in the same manner as in Example 1, except that thethermoplastic resin layer was not formed.

Each of the four color photosensitive transfer materials wassuccessively transferred to a transparent glass substrate, exposed tolight, and developed in the same manner as in Example 1 to form a colorfilter on the glass substrate. After forming a red pattern, each timethe other materials were adhered, air bubbles were entrapped between theglass substrate and the photosensitive resin layer. The resulting colorfiler was observed to suffer from lack of pixels and had poor adhesionto the glass substrate due to the residual air bubbles in the pixels.

EXAMPLE 3

A thermoplastic resin layer having the same formulation as used inExample 1 was coated on a 20 μm thick PET film to a dry thickness of 10μm in the same manner as in Example 1. The same intermediate layer as inExample 1 was then formed thereon to a thickness of 1.5 μm. A coatingcomposition for a photosensitive resin layer having the followingformulation was further coated on the intermediate layer and dried toform a photoresist layer having a thickness of 20 μm.

    ______________________________________                                        Thermoplastic Resin Formulation:                                              ______________________________________                                        Methyl methacrylate/2-ethylhexyl                                                                       15     parts                                         acrylate/benzyl methacrylate/methacrylic                                      acid copolymer (copolymerization molar                                        ratio = 55/28.8/11.7/4.5; Mw = 90000)                                         Polypropylene glycol diacrylate                                                                        6.5    parts                                         (Mw = 822)                                                                    Tetraethylene glycol dimethacrylate                                                                    1.5    parts                                         p-Toluenesulfonamide     0.5    part                                          1,4-Bis(N,N-diethylamino)benzophenone                                                                  0.04   part                                          Benzophenone             1.0    part                                          Malachite Green oxalate  0.02   part                                          3-Morpholinomethyl-1-phenyltriazole-2-                                                                 0.01   part                                          thione                                                                        Leuco Crystal Violet     0.2    part                                          Tribromomethylphenylsulfone                                                                            0.1    part                                          Methyl ethyl ketone      30     parts                                         ______________________________________                                    

A 20 μm thick polyethylene film was laminated on the photoresist layerto prepare a dry film photoresist.

The resulting dry film photoresist material from which the polyethylenefilm had been removed was adhered to a smoothed copper-clad/epoxy resinlayer laminated sheet (the copper-clad had 20 μm of thickness) takingcare not to entrap air bubbles by means of a heat roll laminator.

The PET surface film was stripped off (the releasability of the PET filmwas satisfactory), and the photosensitive resin layer was exposed toultraviolet light through a photomask having a desired circuit patternof a printed board by means of a printer (manufactured by Orc Co., Ltd.)and then developed with a spray of a 1% sodium carbonate aqueoussolution to form an etching resist having a wiring pattern on thecopper-clad laminated sheet. The resulting resist image of the wiringpattern exhibited an extremely high resolving power and suffered from nodefects such as fall-off.

A cupric chloride etchant was then sprayed onto the patternedcopper-clad laminated sheet to dissolve and remove the copper in thearea uncovered with the etching resist. The remaining etching resistlayer was then removed by spraying a 2% sodium hydroxide aqueoussolution thereby to form copper wiring with high resolving power on theepoxy resin base.

COMPARATIVE EXAMPLE 2

A photosensitive transfer material was prepared in the same manner as inExample 3, except that the thermoplastic resin layer was not formed. Aresist pattern was formed on a smoothed copper-clad laminated sheet byusing the resulting photosensitive transfer material in the same manneras in Example 3. The resulting resist pattern was of no practical usedue to many defects of adhesion to the base.

EXAMPLE 4

A multicolor image was formed in the same manner as in Example 1, exceptthat the coating composition for the thermoplastic resin layer(formulation H1) was coated to a dry thickness of 15 μm. No air trappingoccurred at each time of transfer. Each color image suffered from nodefect. The resulting color filter formed on a glass substrate containedno pinholes.

EXAMPLE 5

A dry film photoresist was prepared in the same manner as in Example 3,except that the photoresist layer had a thickness of 10 μm.

An etching resist having a circuit pattern was formed on a copper-cladlaminated sheet in the same manner as in Example 3. The residue of theresin having oozed out from the thermoplastic resin layer on thesubstrate could not observed on the circumference of the substrate. Theresulting resist image exhibited an extremely high resolving power andsuffered from no defects such as fall-off.

A cupric chloride etchant was then sprayed onto the patternedcopper-clad laminated sheet to dissolve and remove the copper in thearea uncovered with the resist. The remaining resist layer was thenremoved by spraying a 2% sodium hydroxide aqueous solution thereby toform copper wiring with high resolving power and accuracy on theglass/epoxy resin base.

COMPARATIVE EXAMPLE 3

Color photosensitive transfer materials were prepared in the same manneras in Example 1, except that formulation for the thermoplastic resinlayer was replaced with the following formulation.

    ______________________________________                                        Formulation:                                                                  ______________________________________                                        Dianal BR85 (acrylic resin produced by                                                                  1.8    parts                                        Mitsubishi Rayon Co., Ltd.; Mw = 250000)                                      Dianal BR77 (acrylic resin produced by                                                                  1.2    parts                                        Mitsubishi Rayon Co., Ltd.; Mw = 80000)                                       Trimethylolpropane triacrylate                                                                          1.22   parts                                        Tetraethylene glycol diacrylate                                                                         0.5    part                                         p-Toluenesulfonamide      0.32   part                                         Benzophenone              0.008  part                                         Methyl ethyl ketone       12.6   parts                                        ______________________________________                                    

No practically usable multicolor image was formed when the resultingcolor photosensitive transfer materials was processed in the same manneras in Example 1. In this case, the thermoplastic resin layer oozed outat the time of transfer to contaminate the laminator roll and, as aresult, the roll contaminated the glass substrate in the subsequenttransfer step. Since the thermoplastic resin layer used was notalkali-soluble, it could not be removed with the aqueous alkalinesolution.

COMPARATIVE EXAMPLE 4

A photosensitive transfer material was prepared in the same manner as inExample 3, except that the thermoplastic resin layer of Example 3 wasreplaced with that used in Comparative Example 3. When a resist patternwas formed on a smoothed copper-clad laminated sheet by using theresulting transfer material in the same manner as in Example 3, nousable image was formed and it was observed that the residue of theresin oozed out from the thermoplastic resin layer remained around theimage area. After etching, the copper layer beneath the resin residueremained unetched.

COMPARATIVE EXAMPLE 5

Color photosensitive transfer materials were prepared in the same manneras in Example 1, except that the intermediate layer was formed by usingthe following formulation containing no polyvinyl pyrrolidone.

    ______________________________________                                        Formulation:                                                                  ______________________________________                                        Polyvinyl alcohol ("PVA 205"                                                                           190 parts                                            produced by Kuraray Co., Ltd.)                                                Fluorine-containing surfactant ("Surfulon                                                              10 parts                                             S-131" produced by Asahi Glass Co., Ltd.)                                     Distilled water          3350 parts                                           ______________________________________                                    

By this method, red, blue, green and black photosensitive transfermaterials were prepared. The red photosensitive transfer material fromwhich the protective sheet had been removed was adhered to a 1.1 mmthick transparent glass substrate under heat (130° C.) and pressure (0.8kg/cm²) by means of a laminator ("VP-II"produced by Taisei Raminator).Thereafter, stripping of the temporary substrate at the interfacebetween the substrate and the thermoplastic resin layer was attempted,but the release at this interface could not the effected and the releasepartly took place between the red photosensitive resin layer and theintermediate layer. As a result, the portion at the red photosensitiveresin layer on the transparent glass substrate where the intermediatelayer had come off together with the temporary substrate underwent theinfluence of oxygen and suffered from a considerable reduction insensitivity.

EXAMPLES 6 TO 10

Temporary substrates (a) to (g) comprising a 100 μm thick PET filmhaving formed on one side thereof a conductive layer having a variedsurface resistivity were prepared.

Preparation of Substrate (a)

In 1000 parts of ethanol were dissolved 65 parts of stannic chloridehydrate and 1.5 parts of antimony trichloride to prepare a uniformsolution. A 1N sodium hydroxide aqueous solution was added theretodropwise until the solution was adjusted to pH 3. The thus formedco-precipitate of colloidal stannic oxide and antimony oxide was allowedto stand at 50° C. for 24 hours to obtain a red brown colloidalprecipitate, followed by centrifugation to separate the precipitate.Water was added to the collected precipitate, followed by centrifugationto remove excess ions. This washing operation was repeated three times.

A hundred parts of the washed precipitate were mixed with 1000 parts ofwater, and the mixture was atomized into a baking furnace set at 650° C.to obtain blue-tinted conductive fine particles having an averageparticle size of 0.15 μm.

The resulting conductive fine particles were dispersed in the followingsystem for 5 hours by means of a paint shaker (manufactured by ToyoSeizai Seisakusho).

    ______________________________________                                        Dispersion System:                                                            ______________________________________                                        Conductive fine particles                                                                              200 parts                                            Saran F-310 (trade name: vinylidene                                                                    10 parts                                             chloride-based copolymer produced                                             by Asahi Dow Ltd.)                                                            Methyl ethyl ketone      150 parts                                            ______________________________________                                    

A coating composition for a conductive layer was prepared according tothe following formulation by using the resulting dispersion of theconductive fine particles.

    ______________________________________                                        Formulation:                                                                  ______________________________________                                        Dispersion prepared above                                                                             15 parts                                              Saran F-310             3 parts                                               Methyl ethyl ketone     100 parts                                             Cyclohexanone           20 parts                                              m-Cresol                5 parts                                               ______________________________________                                    

The resulting coating composition was coated on a 100 μm thick PET filmto a dry weight of 1.3 g/m² and dried at 130° C. for 2 minutes.

Further, a coating composition having the following formulation wascoated thereon to a dry weight of 0.2 g/m² and dried at 130° C. for 1minute.

    ______________________________________                                        Formulation:                                                                  ______________________________________                                        Cellulose triacetate  1      part                                             Methylene dichloride  60     parts                                            Ethylene dichloride   40     parts                                            Erucic amide          0.01   part                                             ______________________________________                                    

Substrate (a) thus prepared had a surface resistivity of 7×10⁸ Ω at 25°C., 25% RH as measured with an insulation resistance meter ("VE-30"manufactured by Kawaguchi Denkyoku K.K.).

Preparation of Substrates (b) to (g)

Substrates (b) to (g) were prepared in the same manner as for substrate(a), except for changing the amount of the conductive fine particles.The surface resistivities of the resulting substrates are shown below.

                  TABLE 2                                                         ______________________________________                                        Substrate   Surface Resistivity                                               ______________________________________                                        (b)         10.sup.10 Ω                                                 (c)         10.sup.11 Ω                                                 (d)         10.sup.12 Ω                                                 (e)         10.sup.13 Ω                                                 (f)         .sup. 10.sup.9 Ω                                            (g)         10.sup.14 Ω                                                 ______________________________________                                    

The same thermoplastic resin layer, intermediate layer andphotosensitive resin layer as used in Example 4 were successively formedon each of substrates (a) to (g) on the side opposite to the conductivelayer. A 12 μm thick polypropylene protective film was bonded bypressing on the photosensitive resin layer to prepare color (red, blue,green, and black) photosensitive transfer materials.

A color filter was formed by using the resulting transfer materials inthe same manner as in Example 1. The resulting color filter obtainedusing the materials each having substrate (a) to (f), respectively,suffered from no lack of pixels and exhibited satisfactory adhesion tothe substrate in each case. Further, no shock of static electricity wasfelt on stripping the temporary substrate in each case.

In the production of a color filter using the transfer materials havingsubstrate (g) or having a substrate (which had a surface resistivity of10¹⁵ Ω) on which not provide a conductive layer, respectively,electrical shock was felt on stripping the temporary substrate. Theresulting color filter had a small number of pinholes in the pixelsattributed to adhered dust.

COMPARATIVE EXAMPLE 6

Color (red, green, blue, and black) photosensitive transfer materialswere prepared in the same manner as in Example 1, except that thethermoplastic resin layer had a thickness of 5 μm.

A color filter was formed on a transparent glass substrate by using theresulting transfer materials in the same manner as in Example 1. In thiscase, after forming a red pattern, each time the other transfermaterials were adhered, air bubbles were entrapped under thephotosensitive resin layer. The resulting color filter was observed tosuffer from lack of pixels and had poor adhesion to the glass substratedue to the residual air bubbles in the pixels.

COMPARATIVE EXAMPLE 7

A photosensitive transfer material was prepared in the same manner as inExample 2, except that the thermoplastic resin layer had a thickness of5 μm. A resist pattern was formed on a smoothed copper-clad laminatedsheet by using the resulting transfer material in the same manner as inExample 3. A pattern image was obtained, but the resulting resist was ofno practical use due to many occurrences of poor adhesion to thesubstrate.

While the invention has been described in detail and with reference tospecific examples thereof, it will be apparent to one skilled in the artthat various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A photosensitive transfer material comprising atemporary substrate having provided thereon an alkali-solublethermoplastic resin layer, an intermediate layer, and a photosensitiveresin layer in this order, the interlaminar adhesion in said transfermaterial being the smallest at the interface between said thermoplasticresin layer and said temporary substrate.
 2. A photosensitive transfermaterial as claimed in claim 1, wherein the temporary substrate is madeof a polyethylene terephthalate, a polycarbonate, a polyethylene, apolypropylene, or a laminate thereof.
 3. A photosensitive transfermaterial as claimed in claim 1, wherein the temporary substrate has athickness of from 5 to 300 μm.
 4. A photosensitive transfer material asclaimed in claim 1, wherein the thermoplastic resin compositionconstituting said thermoplastic resin layer has a softening point of notmore than 80° C.
 5. A photosensitive transfer material as claimed inclaim 4, wherein said thermoplastic resin composition comprises at leastone resin selected from the group consisting of a saponification productof an ethylene-acrylic ester copolymer, a saponification product of astyrene-acrylic ester copolymer, a saponification product of astyrene-methacrylic ester copolymer, a saponification product of avinyltoluene-acrylic ester copolymer, a saponification product of avinyltoluene-methacrylic ester copolymer, a polyacrylate, apolymethacrylate, a saponification product of an acrylic ester-vinylacetate copolymer, and a saponification product of a methacrylicester-vinyl acetate copolymer.
 6. A photosensitive transfer material asclaimed in claim 1, wherein said temporary substrate has a thickness ofat least 6 μm.
 7. A photosensitive transfer material as claimed in claim1, wherein said temporary substrate has a thickness of not more than 100μm.
 8. A photosensitive transfer material as claimed in claim 1, whereinsaid intermediate layer comprises a material which prevents permeationof oxygen into the photosensitive material.
 9. A photosensitive transfermaterial as claimed in claim 1, wherein said intermediate layer issoluble or dispersible in water or an aqueous alkaline solution.
 10. Aphotosensitive transfer material as claimed in claim 1, wherein saidintermediate layer comprises at least one material selected from thegroup consisting of a polyvinyl ether/maleic anhydride polymer, awater-soluble salt of a carboxyalkyl cellulose, a water-soluble celuloseether, a water-soluble salts of carboxyalkylated starch, a polyvinylalcohol, a polyvinyl pyrrolidone, a polyacrylamide, a water-solublepolyamide, a water-soluble salt of polyacrylic acid, gelatin, anethylene oxide polymer, a water-soluble salt of starch and analoguesthereof, a styrene-maleic acid copolymer, and a maleate resin.
 11. Aphotosensitive transfer material as claimed in claim 1, wherein saidintermediate layer comprises a polyvinyl alcohol and polyvinylpyrrolidone.
 12. A photosensitive transfer material as claimed in claim11, wherein said polyvinyl alcohol has a degree of saponification of atleast 80%.
 13. A photosensitive transfer material as claimed in claim12, wherein said intermediate layer comprises polyvinyl pyrrolidone inan amount of from 1 to 75% by weight of the solids content of theintermediate layer.
 14. A photosensitive transfer material as claimed inclaim 1, wherein said intermediate layer has a thickness of from 0.1 to5 μm.
 15. A photosensitive transfer material as claimed in claim 1,wherein said photosensitive resin layer softened and becomes tacky at atemperature of 150° C. or lower.
 16. A photosensitive transfer materialas claimed in claim 1, wherein the photosensitive resin layer comprisesa photosensitive resin composition selected from the group consisting ofa photosensitive composition comprising a negative type diazo resin anda binder, a photopolymerizable composition, a photosensitive resincomposition comprising an azide compound and a binder, and a cinnamicacid-type photosensitive resin composition.
 17. A photosensitivetransfer material as claimed in claim 1, wherein said photosensitiveresin layer has a thickness of from 0.1 μm to 100 μm.
 18. Aphotosensitive transfer material as claimed in claim 1, wherein saidtemporary substrate is a substrate having an electrically conductivelayer having a surface resistivity of not more than 10¹³ Ω or is asubstrate which has been rendered electrically conductive so as to havea surface resistivity of not more than 10¹³ Ω.